Supreme Court ruled in Marbury v. Madison . Any law passed by Congress can be declared unconstitutional by the courts.
The Louisiana Territory was purchased from France for $15 million dollars. The price works out to three cents per acre for the 512 million acres.

1804

12th Amendment changed Presidential election rules.
Jefferson reelected.
Meriwether Lewis and William Clark began exploration of the Northwest.
Vice President Aaron Burr kills Alexander Hamilton in a duel July 11.

1807

Congress outlaws importing slaves from Africa, March 2.
Embargo Act, December 22, forbids American ships to leave American waters.

1808

Slave importation outlawed. Yet, another 1/4 million brought in by 1860.

From the Miller Center of Public Affairs at the University of Virginia, in addition to information on the Presidents themselves, they have first lady and cabinet member biographies, listings of presidential staff and advisers, and timelines detailing significant events in the lives of each administration.

This article by Dennis Montgomery, and originally published in Colonial Williamsburg Journal Vol. 15, No. 3 (Spring 1993) p. 14., addresses more of the personal life of Jefferson, including excerpts from correspondences.

Bears brought back from Lewis and Clark's famous expedition were displayed in cages on the White House lawn. For years the White House was sometimes referred to as the "president's bear garden."

The only presidents to sign the Declaration of Independence, Adams and Jefferson both died on its 50th anniversary, July 4, 1826. Adams' dying words were "Thomas Jefferson survives". Jefferson, however, had passed on a few hours earlier.

Jefferson is credited with several inventions, including the swivel chair, a pedometer, a machine to make fiber from hemp, a letter-copying machine, and the lazy susan.

Jefferson wrote his own epitaph without mentioning that he served as president of the United States.